6mr1

Structural highlights

Function

CCMM_THEVB Functions as a scaffold protein for the assembly of beta-carboxysomes, initiates carboxysome assembly by coalescing RuBisCO (ribulose bisphosphate carboxylase, rbcL-rbcS) (Probable). Produced as a full-length and a shorter form; both forms are required for correct carboxysome assembly and growth (By similarity).[UniProtKB:Q03513]^[1] A carbonic anhydrase, catalyzes the reversible hydration of carbon dioxide. Essential to photosynthetic carbon dioxide fixation, supplies CO(2) to ribulose bisphosphate carboxylase (RuBisCO) in the carboxysome. Active when the disulfide bond (194-200) is oxidized, suggesting the interior of the carboxysome is oxidizing.^[2] Beta-carboxysome assembly initiates when soluble RuBisCO is condensed into a liquid matrix in a pre-carboxysome by the RbcS-like domains of probably both forms of CcmM (Probable). CcmN interacts with the N-terminus of full length CcmM, and then recruits the shell proteins (CcmK) via CcmN's encapsulation peptide. Shell formation requires both CcmK proteins and CcmO. CcmL caps the otherwise elongated carboxysome. Once fully encapsulated carboxysomes are formed, they migrate within the cell probably via interactions with the cytoskeleton (By similarity).[UniProtKB:Q03513]^[3]

References

1. ↑ Ryan P, Forrester TJB, Wroblewski C, Kenney TMG, Kitova EN, Klassen JS, Kimber MS. The small RbcS-like domains of the beta-carboxysome structural protein, CcmM, bind RubisCO at a site distinct from that binding the RbcS subunit. J Biol Chem. 2018 Dec 27. pii: RA118.006330. doi: 10.1074/jbc.RA118.006330. PMID:30591587 doi:http://dx.doi.org/10.1074/jbc.RA118.006330
2. ↑ Pena KL, Castel SE, de Araujo C, Espie GS, Kimber MS. Structural basis of the oxidative activation of the carboxysomal gamma-carbonic anhydrase, CcmM. Proc Natl Acad Sci U S A. 2010 Feb 9;107(6):2455-60. Epub 2010 Jan 25. PMID:20133749
3. ↑ Ryan P, Forrester TJB, Wroblewski C, Kenney TMG, Kitova EN, Klassen JS, Kimber MS. The small RbcS-like domains of the beta-carboxysome structural protein, CcmM, bind RubisCO at a site distinct from that binding the RbcS subunit. J Biol Chem. 2018 Dec 27. pii: RA118.006330. doi: 10.1074/jbc.RA118.006330. PMID:30591587 doi:http://dx.doi.org/10.1074/jbc.RA118.006330